Knowing you are in a chemistry class, your elderly uncle shows up at your place in a panic. He is about to go a dental procedure for which his oral surgeon suggest light sedation by diazepam(valium). He is concern about how long the effects will last since your cousin's wedding is tonight, especially since his doctor mentioned differences elimination kinetics in older people. The oral surgeon prescribed a 10mg tablet to be taken at 9am, an hour before the procedure. The doctor will give an IV with up to 10mg more during the procedure. Your uncle weights about 170lbs and is 72 years old. Can you explain to him about how long the medicine will last and the doctor's concern about older people? Draw/ find a graph to help him understand.